Kamiwazumi Jun is a high school student down on his luck. One day, he finds a girl fainted and stark naked in front of his house, who later explains she is on a mission from the future to protect him, the eventual saviour of humankind. With the help of tools from her 'ninth-dimensional pocket,' Jun's life is about to take a turn for better or worse as he entrusts his daily life into the hands of this mysterious girl...